Merge pull request #144 from codeharborhub/dev-1

Doneprogramming fundamentals

Author: ajay-dhangar

docs/machine-learning/programming-fundamentals/basic-syntax/conditionals.mdx

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+---
+title: Conditionals and Branching
+sidebar_label: Conditionals
+description: "Mastering If, Else, and Elif statements to control program flow and handle logic in Machine Learning pipelines."
+tags: [python, programming, logic, conditionals, branching, mathematics-for-ml]
+---
+
+Machine Learning is often about making decisions. **Conditionals** allow our code to react differently depending on the input. Whether it's checking if a dataset is empty or deciding which model to load, `if-else` logic is the foundation of programmatic decision-making.
+
+## 1. The `if`, `elif`, and `else` Structure
+
+Python uses indentation to define the scope of conditional blocks.
+
+```python
+accuracy = 0.85
+
+if accuracy > 0.90:
+    print("Excellent model performance!")
+elif accuracy > 0.70:
+    print("Good performance, but could be improved.")
+else:
+    print("Model needs retraining.")
+
+```
+
+```mermaid
+flowchart TD
+    Start([Check Accuracy]) --> C1{Acc > 0.90?}
+    C1 -- Yes --> R1[Print: Excellent]
+    C1 -- No --> C2{Acc > 0.70?}
+    C2 -- Yes --> R2[Print: Good]
+    C2 -- No --> R3[Print: Retrain]
+
+```
+
+## 2. Comparison and Logical Operators
+
+Conditionals rely on boolean expressions that evaluate to either `True` or `False`.
+
+### A. Comparison Operators
+
+* `==` (Equal to)
+* `!=` (Not equal to)
+* `>` / `<` (Greater/Less than)
+* `>=` / `<=` (Greater/Less than or equal to)
+
+### B. Logical Operators (Chaining)
+
+* `and`: Both conditions must be True.
+* `or`: At least one condition must be True.
+* `not`: Reverses the boolean value.
+
+```python
+# Check if learning rate is within a safe range
+lr = 0.001
+if lr > 0 and lr < 0.1:
+    print("Learning rate is valid.")
+
+```
+
+## 3. The "ReLU" Example: Math meets Logic
+
+One of the most famous conditional operations in Deep Learning is the **Rectified Linear Unit (ReLU)** activation function.
+
+$$ 
+\text{ReLU}(x) = \max(0, x) 
+$$
+
+In Python code, this is a simple conditional:
+
+```python
+def relu(x):
+    if x > 0:
+        return x
+    else:
+        return 0
+
+```
+
+## 4. Truthiness and Identity
+
+In ML data cleaning, we often check if a variable actually contains data.
+
+* **Falsy values:** `None`, `0`, `0.0`, `""` (empty string), `[]` (empty list), `{}` (empty dict).
+* **Truthy values:** Everything else.
+
+```python
+features = get_features()
+
+if not features:
+    print("Warning: No features found in dataset!")
+
+```
+
+### `is` vs `==`
+
+* `==` checks for **Value equality** (Are the numbers the same?).
+* `is` checks for **Identity** (Are they the exact same object in memory?).
+
+## 5. Inline Conditionals (Ternary Operator)
+
+For simple logic, Python allows a one-liner known as a ternary operator.
+
+```python
+# status = "Spam" if probability > 0.5 else "Not Spam"
+prediction = "Positive" if y_hat > 0.5 else "Negative"
+
+```
+
+## 6. Match-Case (Python 3.10+)
+
+For complex branching based on specific patterns (like different file extensions or model types), the `match` statement provides a cleaner syntax than multiple `elif` blocks.
+
+```python
+optimizer_type = "adam"
+
+match optimizer_type:
+    case "sgd":
+        print("Using Stochastic Gradient Descent")
+    case "adam":
+        print("Using Adam Optimizer")
+    case _:
+        print("Using Default Optimizer")
+
+```
+
+---
+
+Decision-making is key, but to keep our code clean, we shouldn't repeat our logic. We need to wrap our conditionals and loops into reusable components.

docs/machine-learning/programming-fundamentals/basic-syntax/data-structures.mdx

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+---
+title: Data Structures
+sidebar_label: Data Structures
+description: "Mastering Python's built-in collections: Lists, Tuples, Dictionaries, and Sets, and their specific roles in data science pipelines."
+tags: [python, data-structures, lists, dictionaries, tuples, sets, mathematics-for-ml]
+---
+
+While basic types hold single values, **Data Structures** allow us to group, organize, and manipulate large amounts of information. In ML, choosing the wrong structure can lead to code that runs $100\times$ slower than it should.
+
+## 1. Lists: The Versatile Workhorse
+
+A **List** is an ordered, mutable collection of items. Think of it as a flexible array that can grow or shrink.
+
+* **Syntax:** `my_list = [0.1, 0.2, 0.3]`
+* **ML Use Case:** Storing the history of "Loss" values during training so you can plot them later.
+
+```python
+losses = []
+for epoch in range(10):
+    current_loss = train_step()
+    losses.append(current_loss) # Dynamic growth
+
+```
+
+## 2. Tuples: The Immutable Safeguard
+
+A **Tuple** is like a list, but it **cannot be changed** after creation (immutable).
+
+* **Syntax:** `shape = (224, 224, 3)`
+* **ML Use Case:** Defining image dimensions or model architectures. Since these shouldn't change accidentally during execution, a tuple is safer than a list.
+
+```mermaid
+graph LR
+    L[List: Mutable] --> L_Edit["Can change: my_list[0] = 5"]
+    T[Tuple: Immutable] --> T_Edit["Error: 'tuple' object does not support assignment"]
+    style T fill:#fffde7,stroke:#fbc02d,color:#333
+
+```
+
+## 3. Dictionaries: Key-Value Mapping
+
+A **Dictionary** stores data in pairs: a unique **Key** and its associated **Value**. It uses a "Hash Table" internally, making lookups incredibly fast ( complexity).
+
+* **Syntax:** `params = {"learning_rate": 0.001, "batch_size": 32}`
+* **ML Use Case:** Managing hyperparameters or mapping integer IDs back to human-readable text labels.
+
+```mermaid
+graph TD
+    Key["Key: 'Cat'"] --> Hash["Hash Function"]
+    Hash --> Index["Memory Index: 0x42"]
+    Index --> Val["Value: [0.98, 0.02, ...]"]
+    style Hash fill:#e1f5fe,stroke:#01579b,color:#333
+
+```
+
+## 4. Sets: Uniqueness and Logic
+
+A **Set** is an unordered collection of **unique** items.
+
+* **Syntax:** `classes = {"dog", "cat", "bird"}`
+* **ML Use Case:** Finding the unique labels in a messy dataset or performing mathematical operations like Union and Intersection on feature sets.
+
+## 5. Performance Comparison
+
+Choosing the right structure is about balancing **Speed** and **Memory**.
+
+| Feature | List | Tuple | Dictionary | Set |
+| --- | --- | --- | --- | --- |
+| **Ordering** | Ordered | Ordered | Ordered (Python 3.7+) | Unordered |
+| **Mutable** | **Yes** | No | **Yes** | **Yes** |
+| **Duplicates** | Allowed | Allowed | Keys must be unique | Must be unique |
+| **Search Speed** |  (Slow) |  (Slow) |  (Very Fast) |  (Very Fast) |
+
+```mermaid
+xychart-beta
+    title "Search Speed (Lower is Better)"
+    x-axis ["List", "Tuple", "Set", "Dict"]
+    y-axis "Time Complexity" 0 --> 120
+    bar [100, 100, 5, 5]
+
+```
+
+## 6. Slicing and Indexing
+
+In ML, we often need to "slice" our data (e.g., taking the first 80% for training and the last 20% for testing).
+
+$$ 
+\text{Syntax: } \text{data}[\text{start} : \text{stop} : \text{step}] 
+$$
+
+```python
+data = [10, 20, 30, 40, 50, 60]
+train = data[:4]  # [10, 20, 30, 40]
+test = data[4:]   # [50, 60]
+
+```
+
+---
+
+Now that we can organize data, we need to control the flow of our program—making decisions based on that data and repeating tasks efficiently.

docs/machine-learning/programming-fundamentals/basic-syntax/exceptions.mdx

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+---
+title: Exception Handling
+sidebar_label: Exceptions
+description: "Learning to handle errors gracefully in Python to build robust and fault-tolerant Machine Learning pipelines."
+tags: [python, programming, exceptions, error-handling, debugging, mathematics-for-ml]
+---
+
+In Machine Learning, things often go wrong: a dataset file is missing, a GPU runs out of memory, or a feature contains a `NaN` (Not a Number) that crashes a calculation. **Exception Handling** allows your program to "fail gracefully" rather than crashing completely.
+
+## 1. The Try-Except Block
+
+The basic tool for handling errors is the `try...except` block. You "try" a piece of code, and if it raises an error, the "except" block catches it.
+
+```python
+try:
+    # Attempting to load a large dataset
+    data = load_dataset("huge_data.csv")
+except FileNotFoundError:
+    print("Error: The dataset file was not found. Please check the path.")
+
+```
+
+```mermaid
+flowchart TD
+    Start([Start Try Block]) --> Op[Execute Code]
+    Op --> Success{Error Occurred?}
+    Success -- No --> End([Continue Program])
+    Success -- Yes --> Catch[Match Exception Type]
+    Catch --> Handle[Execute Except Block]
+    Handle --> End
+    style Catch fill:#ffebee,stroke:#c62828,color:#333
+
+```
+
+## 2. Handling Multiple Exceptions
+
+Different operations can fail in different ways. You can catch specific errors to provide tailored solutions.
+
+* **`ValueError`**: Raised when a function receives an argument of the right type but inappropriate value (e.g., trying to take the square root of a negative number).
+* **`TypeError`**: Raised when an operation is applied to an object of inappropriate type.
+* **`ZeroDivisionError`**: Common in manual normalization logic.
+
+```python
+try:
+    result = total_loss / num_samples
+except ZeroDivisionError:
+    result = 0
+    print("Warning: num_samples was zero. Setting loss to 0.")
+except TypeError:
+    print("Error: Check if total_loss and num_samples are numbers.")
+
+```
+
+## 3. The Full Lifecycle: `else` and `finally`
+
+To build truly robust pipelines (like those that open and close database connections), we use the extended syntax:
+
+1. **`try`**: The code that might fail.
+2. **`except`**: Code that runs only if an error occurs.
+3. **`else`**: Code that runs only if **no** error occurs.
+4. **`finally`**: Code that runs **no matter what** (perfect for closing files or releasing GPU memory).
+
+```python
+try:
+    file = open("model_weights.bin", "rb")
+    weights = file.read()
+except IOError:
+    print("Could not read file.")
+else:
+    print("Weights loaded successfully.")
+finally:
+    file.close()
+    print("File resource released.")
+
+```
+
+## 4. Raising Exceptions
+
+Sometimes, you *want* to stop the program if a specific condition isn't met. For example, if a user provides a negative learning rate.
+
+```python
+def set_learning_rate(lr):
+    if lr <= 0:
+        raise ValueError(f"Learning rate must be positive. Received: {lr}")
+    return lr
+
+```
+
+## 5. Exceptions in ML Data Pipelines
+
+In production ML, we use exceptions to ensure data quality.
+
+```mermaid
+graph LR
+    Input[Data Source] --> Check{Check Data}
+    Check -->|Valid| Train[Start Training]
+    Check -->|Corrupted| Exc[Raise DataValidationError]
+    Exc --> Log[Log Error to Dashboard]
+    Exc --> Fallback[Use Last Known Good Data]
+    style Exc fill:#ffc107,stroke:#ff8f00,color:#333
+
+```
+
+## 6. Summary of Common ML Exceptions
+
+| Exception | When it happens in ML |
+| --- | --- |
+| **`IndexError`** | Trying to access a non-existent column or row index in an array. |
+| **`KeyError`** | Looking for a hyperparameter in a config dictionary that doesn't exist. |
+| **`AttributeError`** | Calling a method (like `.predict()`) on a model that hasn't been trained yet. |
+| **`MemoryError`** | Loading a dataset that is larger than the available RAM. |
+
+---
+ 
+Handling errors ensures your code doesn't crash, but how do we organize our code so it's easy to read and maintain? Let's explore the world of Classes and Objects.